Make DefaultValueAttribute fall back to TypeConverter

ericstj · Aug 7, 2018 · 17ac7be · 17ac7be
1 parent ab9b451
commit 17ac7be
Showing 1 changed file with 30 additions and 1 deletion.
diff --git a/src/System.Private.CoreLib/shared/System/ComponentModel/DefaultValueAttribute.cs b/src/System.Private.CoreLib/shared/System/ComponentModel/DefaultValueAttribute.cs
@@ -22,6 +22,7 @@ public class DefaultValueAttribute : Attribute
         ///     This is the default value.
         /// </devdoc>
         private object _value;
+        private static Func<Type, string, object> s_convertMethod = GetConvertMethod();
 
         /// <devdoc>
         /// <para>Initializes a new instance of the <see cref='System.ComponentModel.DefaultValueAttribute'/> class, converting the
@@ -44,16 +45,44 @@ public DefaultValueAttribute(Type type, string value)
                 {
                     _value = TimeSpan.Parse(value);
                 }
-                else
+                else if (type.Module == typeof(string).Module)
                 {
                     _value = Convert.ChangeType(value, type, CultureInfo.InvariantCulture);
                 }
+                else
+                {
+                    _value = s_convertMethod(type, value);
+                }
             }
             catch
             {
             }
         }
 
+        private static Func<Type, string, object> GetConvertMethod()
+        {
+            var typeDescriptorType = Type.GetType(
+                "System.ComponentModel.TypeDescriptor, System, Version=0.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089",
+                throwOnError: false);
+            var typeConverterType = Type.GetType(
+                "System.ComponentModel.TypeConverter, System, Version=0.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089",
+                throwOnError: false);
+
+            if (typeDescriptorType != null && typeConverterType != null)
+            {
+                var typeDescriptorTypeGetConverter = typeDescriptorType.GetMethod("GetConverter", new Type[] { typeof(Type) });
+                var typeConverterConvertFromInvariantString = typeConverterType.GetMethod("ConvertFromInvariantString", new Type[] { typeof(string) });
+                return new Func<Type, string, object>((t, s) =>
+                    typeConverterConvertFromInvariantString.Invoke(
+                        typeDescriptorTypeGetConverter.Invoke(null, new[] { t }),
+                        new[] { s }));
+            }
+            else
+            {
+                return new Func<Type, string, object>((t, s) => null);
+            }
+        }
+
         /// <devdoc>
         /// <para>Initializes a new instance of the <see cref='System.ComponentModel.DefaultValueAttribute'/> class using a Unicode
         ///    character.</para>